A documentary study of the felt effects of the great California earthquake of 1857

摘要: We have collected over 60 hitherto unpublished accounts of the California earthquake January 9, 1857. used them, together with those already known, to estimate felt intensities and prepare an isoseismal map which roughly indicates level short-period ground motion experienced during this earthquake. Modified Mercalli VI VII occurred in modern metropolitan areas southern California, VIII San Joaquin Valley. The intensity along fault was IX or more. Instances seiching, fissuring, sandblows, hydrologic changes were reported from Sacramento Colorado River delta. Most reports say that shaking lasted between one three minutes. At least two large aftershocks within a week main event.